[src/trunk]: src/sys/kern execve_runproc: Simplify &argc address calc. The s...

[uebayasi <uebayasi%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/351021c7ea8e
branches:  trunk
changeset: 328729:351021c7ea8e
user:      uebayasi <uebayasi%NetBSD.org@localhost>
date:      Tue Apr 15 16:13:04 2014 +0000

description:
execve_runproc: Simplify &argc address calc.  The set of (argc, argv, ...)
is located just "behind" the initial SP.  SHRINK, then ALLOC, and you get
&argc.

diffstat:

 sys/kern/kern_exec.c |  32 ++++++++------------------------
 1 files changed, 8 insertions(+), 24 deletions(-)

diffs (66 lines):

diff -r 719471f159ee -r 351021c7ea8e sys/kern/kern_exec.c
--- a/sys/kern/kern_exec.c      Tue Apr 15 15:50:16 2014 +0000
+++ b/sys/kern/kern_exec.c      Tue Apr 15 16:13:04 2014 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: kern_exec.c,v 1.396 2014/04/15 15:50:16 uebayasi Exp $ */
+/*     $NetBSD: kern_exec.c,v 1.397 2014/04/15 16:13:04 uebayasi Exp $ */
 
 /*-
  * Copyright (c) 2008 The NetBSD Foundation, Inc.
@@ -59,7 +59,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_exec.c,v 1.396 2014/04/15 15:50:16 uebayasi Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_exec.c,v 1.397 2014/04/15 16:13:04 uebayasi Exp $");
 
 #include "opt_exec.h"
 #include "opt_execfmt.h"
@@ -1065,28 +1065,13 @@
         * in setregs().
         */
 
-       const size_t sigcode_psstr_sz =
-           data->ed_szsigcode +        /* sigcode */
-           data->ed_ps_strings_sz +    /* ps_strings */
-           STACK_PTHREADSPACE;         /* pthread space */
-
-       char                    *stack;
-
-       /* Top of the stack address space. */
-       stack = vm->vm_minsaddr;
+       char * const newstack = STACK_GROW(vm->vm_minsaddr, epp->ep_ssize);
 
-       /* Skip pthread space, ps_strings, and sigcode. */
-       stack = STACK_GROW(stack, sigcode_psstr_sz);
-
-       /* Allocate the gap for _rtld() and arguments to be filled by copyargs(). */
-       stack = STACK_ALLOC(stack, epp->ep_ssize - sigcode_psstr_sz);
+       char *newargs = STACK_ALLOC(
+           STACK_SHRINK(newstack, data->ed_argslen), data->ed_argslen);
 
-       /* Skip a few words reserved for _rtld(). */
-       stack = STACK_GROW(stack, RTLD_GAP);
-
-       /* Now copy argc, args & environ to the new stack. */
        error = (*epp->ep_esch->es_copyargs)(l, epp,
-           &data->ed_arginfo, &stack, data->ed_argp);
+           &data->ed_arginfo, &newargs, data->ed_argp);
 
        if (epp->ep_path) {
                PNBUF_PUT(epp->ep_path);
@@ -1191,12 +1176,11 @@
         * the end of arg/env strings.  Userland guesses the address of argc
         * via ps_strings::ps_argvstr.
         */
-       const vaddr_t newstack = (vaddr_t)STACK_GROW(vm->vm_minsaddr, epp->ep_ssize);
 
        /* Setup new registers and do misc. setup. */
-       (*epp->ep_esch->es_emul->e_setregs)(l, epp, newstack);
+       (*epp->ep_esch->es_emul->e_setregs)(l, epp, (vaddr_t)newstack);
        if (epp->ep_esch->es_setregs)
-               (*epp->ep_esch->es_setregs)(l, epp, newstack);
+               (*epp->ep_esch->es_setregs)(l, epp, (vaddr_t)newstack);
 
        /* Provide a consistent LWP private setting */
        (void)lwp_setprivate(l, NULL);